This invention relates to spring-loaded casters and, more particularly, to lever action casters with shock absorbing springs.
Mechanisms are known to mount wheels as, for example, via casters and with the wheel being secured in a manner that with increased loading the support for the wheel becomes deflected as by the deflection of a spring.
Previously known devices suffer the disadvantage that it is difficult to know whether a spring-loaded caster is being subjected to loads which exceed preferred operational limits for the spring.
Previously known devices also suffer the disadvantage that relatively complex structures are required for mounting of a wheel to a support so as to permit the wheel to be supported in a spring biased manner.
To at least partially overcome the disadvantages of the previously known devices, the present invention provides a caster carrying a gauge by which the load carried by the caster is displayed visible to a user. The invention is directed to provide an indicating system such that the caster can be visually inspected to determine the load which it is bearing and to see if it is within preferred limits.
To overcome disadvantages of the previously known devices, the present invention also provides a simplified construction for a wheel mount in which the supporting structure itself deflects under loads.
An object of the present invention is to provide in a spring-loaded caster, an indicating system such that the caster can be visually inspected to see the load which it is bearing.
Another object is to provide a simplified support for mounting a wheel in which the support structure itself deflects under load.
Another object is to provide a simplified construction for a spring-loaded caster in which a support for the wheel comprises a unitary element.
The invention provides a spring-loaded caster with an indicator to indicate the load applied to the caster. The spring-loaded caster has a wheel mounted to a lever which pivots relative a support against the bias of a spring when loads are applied. The indicator preferably has a first indicator component on the lever and a second indicator component on the support. The two indicator components are located adjacent each other so that their relative positions indicate loading on the caster and can be easily seen by the human eye while the caster is in use.
Swiveling casters typically swivel about a substantially vertical swivel axis. The caster has a wheel which is journalled for rotation about a horizontal wheel axis. The wheel axis is typically horizontally spaced from an extension of the swivel axis and this spacing or offset frequently is a significant factor in determining safe loads which can be carried without failure. The present invention is particularly advantageous with swiveling casters where wheel axis are offset from the swivel axis. In providing a load indicating system, a method is provided preferably sensed visually by which loads can be kept in a safe range. Sensing, of course, could also be via electronic or other automatic indication and sensing devices than merely visual inspection or indication.
The invention also provides a novel construction for a wheel mount assembly in which a resilient member can serve to couple the wheel supporting lever to a support for deflection to provide relative movement of the lever and support under varying loads. The resilient member can serve as a primary biasing device which resists relative movement of the lever and support or can be complemented by an additional spring.
In one aspect, the present invention provides a caster assembly comprising a mounting member mountable to an article,
a support member mounted to the mounting member for swiveling about a support axis,
an elongate lever pivotably coupled to the support member for pivoting of the lever relative the support member about a pivot axis generally normal to the support axis,
a wheel rotatably mounted to the lever for rotation about a wheel axis spaced from the pivot axis and parallel the pivot axis;
a spring member disposed between the lever and the support member such that pivoting of the lever relative the support member about the pivot axis at least in one direction deflects the spring member,
a support indicator carried by the support member spaced from the pivot axis radially relative the pivot axis,
a lever indicator carried by the lever spaced from the pivot axis radially relative the pivot axis,
the support indicator and lever indicator disposed in juxtapositioned complementary relation to move relative each other on pivoting of the lever relative the support member about the pivot axis and provide a visual indication of the extent of deflection of the spring member.
In another aspect, the present invention provides a wheel support assembly comprising a support member adapted to be coupled to an article,
an elongate lever member having a first end and a second end,
a first spring member coupling the first end of the lever member to the support member,
a wheel rotatably mounted to the second end of the lever member for rotation about a wheel axis spaced from the first spring member,
the first spring member comprising a resilient member which on deflection under loads applied to the wheel assembly moves the second end of the lever member carrying the wheel relatively closer to or farther away from the support member between extended and retracted positions while maintaining the wheel axis in all different positions between the extended and retracted positions parallel the orientation of the wheel axis in the extended position.
In another aspect, the present invention provides a wheel assembly comprising:
an elongate generally U-shaped flex member having a first leg and a second leg joined by a bridging bight,
the first leg comprising a support portion adapted to be secured to an article,
the second leg having a wheel rotatably mounted thereto for rotation about a wheel axis,
the bight comprising a resilient first spring member which resiliently deflects under loads applied between the support portion and the wheel to move the wheel relatively closer to or farther away from the support portion between respective retracted and extended positions,
the flex member maintaining the wheel axis in all different positions between the retracted position and the extended position parallel an orientation of the wheel axis in the extended position.
In another aspect, the present invention provides a wheel support assembly comprising:
a support member adapted to be coupled to an article,
a spring member having a first end and a second end,
an lever member having a first end and a second end,
a wheel rotatably mounted to the second end of the lever for rotation about a wheel axis,
the first end of the spring member fixedly secured to the support member and the first end of the lever member fixedly secured to the second end of the spring member, whereby the spring member and lever member together comprise a continuous appendage extending from the support member and supporting the wheel at a distal end,
the spring member deflecting under loads applied between the support member and the wheel to move the wheel relatively closer to the support member under increasing loads.